The invention relates to a box for equipment such as electronic components incorporating heat sources distributed in accordance with a given cartography. More specifically, the invention relates to a box essentially made from a thermally insulating material and having means of a passive nature making it possible to dissipate the heat given off by the equipment contained therein.
Although the invention is particularly adapted to the case of a box containing electronic circuits or components of various types, it is not limited to said application and covers all cases where equipment containing heat sources is located in a box. The heat sources can be constituted by active components such as transistors and passive components such as resistors.
At present, electronic equipment is usually installed in metal boxes. The nature of the metal from which these boxes are made is generally determined as a function of the envisaged application. The metals used all have a good capacity for conducting and dissipating the heat given off within the box by the electronic components. By placing the components with the greatest heat dissipation against the box wall, or by interposing between said components and the box wall a member which ensures a good thermal conductivity, the transfer and dissipation of heat are readily ensured. An illustration of this state of the art is provided by U.S. Pat. No. 4,330,812.
When the heat to be dissipated is greater, cooling ribs or fins can be provided on the outer face of the box wall, so as to increase the efficiency of convection phenomena. The heat dissipation obtained in this way is of a passive nature, because it does not have recourse to any auxiliary energy source.
These passive heat dissipation methods can be completed, if necessary, by procedures of an active nature when the heat quantities to be dissipated exceed the possibilities offered by the materials used. Among these active procedures, reference is made to internal or external ventilation, the addition of Peltier modules and the use of state change fluid circuits.
It is firstly pointed out that the invention only relates to passive heat dissipation methods. These methods can possibly be completed by those of an active nature, when this is justified by the heat quantities to be dissipated.
All known passive heat dissipation methods are based on the use of a box essentially made from a thermally conductive material.
However, certain applications may require the use for the production of said boxes of thermally insulating materials, such as moulded composite materials. Among these applications are all cases where a weight gain is desirable, which is particularly the case for electronic component boxes used in the aeronautical and space fields. The use of thermally insulating materials can be justified through their reduced cost, particularly in the general electronics field.
In these special applications, the traditional methods for ensuring the passive dissipation of the heat given off within boxes cannot be used. It is therefore necessary to use new passive heat dissipation methods, if it is not wished to use active methods in all cases, such methods being heavy and onerous.